Ring forming method and apparatus



March 25, 1958 G. R. SQUIBB 2,827,688

I RING FORMING METHOD AND APPARATUS Filed June 9, 1951 I 4 Sheets-Sheet l 3nnentor i 1 62%? ji 25 2 I BB 1 N W E attorneg March 25, 1958 e. R. SQUIBB 2,327,688

RING FORMING METHOD AND APPARATUS Filed June 9, 195] 4 Sheets-Sheet 2 Zhmcntor (Ittonwgs March 25, 8 G. R. SQUIBB 2,327,588

RING FORMING METHOD AND APPARATUS Filed June 9, 1951 4 Sheets-Sheet 3 aga $521??? 5 f I c (Ittornegs March 25, 1958 Filed June 9, 195] G. R. SQUIBB 2,827,688

RING FQRMING METHOD AND APPARATUS 4 Sheets-Sheet 4 2,327,688 Patented Mar. 25, 1958 RING noun into Murnoo AND APPARATUS Application '9, 1951, erial No. 23%,761

3 Claims.

This invention relates to a method of and an apparatus for making split rings for use as piston rings in the cylinders of internal combustion engines and for other purposes.

An object of the invention is to reduce the time, the number of operations, and the equipment and labor which heretofore have been required in the making of piston rings from continuous round steel Wire.

Another object of the invention is to provide a method of and an apparatus for more economically forming, cut-ting off, and normalizing the internal stresses resulting from the forming of split rings which thereafter may be economically finished to provide piston rings for the cylinders of internal combustion engines and for other purposes.

Another object of the invention is to provide normalized split rings made from continuous steel wire, and having an external configuration on each ring which is only slightly larger than the ring after being finished by honing or grinding the external surface thereof.

Another object of the invention is economically to employ preformed steel wire to form normalized split rings having an increasing curvature from the middle of each ring toward the ends thereof. Such rings may be made to exert substantially equal resilient forces in all directions when contracted within a circular finishing tool and when finished, may he made to exert substantially equal resilient forces in all irections around the interior of a cylinder in which the ring may be employed as a piston ring or for other purposes.

Another object of the invention is to reduce the time and the expense which heretofore has been required for heat training piston rings to normalize the internal stresses therein. Such reduction in time and expense may be secured by forming the rings in the configuration in which the rings are to be rigidly held in the heat treating fixture employed.

It is proposed to employ a continuous length of preformed steel wire to form split rings that increase in curvature from the middle toward the opposite ends of each ring. The curvature proposed is such that the rings will exert substantially uniform radial pressure against the interior surface of a cylindrical finishing tool which may be employed in later operations for grinding or honing the exterior surfaces of the rings. It is also proposed to form the rings to such configuration in order that the rearrangement of the molecular structure of the steel, which takes place during the heat treating operation, will be only the necessary rearrange -ent of molecules required to relieve the internal stresses caused by bending the wire to the ultimate configuration desired. It will not be necessary to relieve the stresses which heretofore have resulted from forming the rings to the ultimate configuration referred to, in the heat treating apparatus in which such rings heretofore also have been formed in the desired ultimate configuration. It is therefore proposed to form split rings for making piston rings in an apparatus for bending and cutting of]? wire, and then to secure the rings in heat treating fixture in the form in which they were bent by the bending apparatus, for normalizing the illternal stresses resulting from bending the wire. For a better understanding of the invention, reference may now be had to the accompanying drawing forming a part of this specification, in which: Figure l is a fragmentary plan view of an apparatus for bending and cutting ofi successive lengths of steel wire, according to the principles of the invention.

Figure 2 is a fragmentary vertical sectional view of theapparatus shown by Figure 1. Figure 2 particularly lllustrates the wire holding, ring forming and cut-off mech anisms employed in the apparatus disclosed by Figure 'l' and is taken substantially in the plane of line 22 oir" Figure 1. r 1' Figure 3 is a transverse sectional view through a part of the apparatus disclosed by Figure 2, as the structure would appear substantially in the plane of line 3-3 on Figure 2. Figure 4 is a view diagrammatically illustrating a heat treating furnace and fixture employed in practicing the? invention. 2 Figure 5 is another transverse sectional view of the apparatus as the latter would appear substantiallyinthe plane of line 5-5 on Figure 1, looking in the direction of the arrows thereon. Figure 5 particularly illustrates the mechanism for holding the wire while a previously formed ring is cut oil.

Figure 6 is a fragmentary horizontal sectional view-of the wire holding mechanism illustrated by Figure 5- and taken substantially in the plane of line 6--6 on Figure 51* Figure 7 is a diagrammatical illustration of the method of and apparatus for bending a wire to form a splitring' in the ultimate configuration desire The apparatus disclosed by Figure 1 comprises a ma'. chine frame it) having bearings in which a plurality of shafts indicated at 11, 12, and 13 employed in operating the apparatus, are iournaled. The shafts ll, 12, and 13 may be connected to one another by gears, not shown, and may be driven simultaneously and at the proper relative speeds by a single motor or other suitable means; not shown. 3 The principal mechanical elements of the apparatus dis closed by Figure l comprise an intermittent Wire feeding mechanism 14, a wire holding mechanism 16, a wirebending mechanism 17 and a ring cut-oil mechanism 18. T he intermittent wire feeding mechanism 14 is similar" to that shown by Burton Patent 1,959,853, dated May" 22, 1934. The wire feeding mechanism 14 comprises a clamping head 19 which is mounted on parallel rails 21' having the opposite ends thereof secured in transverse frame members 22 and 23 supported by the frame 13 0f the machine. The head 19 carries a block 24 at one side thereof through an opening in which projects a continuousi high carbon or other suitable steel wire 25 comprising the stock from which the rings made by the machine are; formed. The head 19 comprises an internally disposed eccentric member having a part which projects into the block 24 to engage and clamp the Wire 25 during-themovement of the head into the advanced position shown by Figure l. The eccentric part referred to releases the-- wire when the head is retracted from the positionshowna- The head 19 is advanced into and retracted from the;

position shown in Figure l by a link 27 which is pivotally secured at one end to a lug Z3 projecting rearwardly from the hea 1?. The opposite end of the link 27 is likewise" pivotally secured to the upper end of a lever 29' having an intermediate portion pivotally mounted upon the frame 1% and the opposite end thereof operatively associated with an eccentric 31 rigidly, secured to and rotated by. the shaft 12. It will be apparent that rotation ofthei. eccentric 31 will oscillate the lever 29 in such manner as to impart reciprocating movement to the. head 19 through the link 27. The mechanism for reciprocating the head 19 upon theirails 21 is adjustable throughout any a desired; length of stroke, andfthe length of stroke of the 'headdetermines the length by which the wire 26 will be advancedupon each reciprocating movement of :the head. The wire 26 is advanced toward the wire clamping mechanism 16 through a tube 32 having theopposite ends 7 thereof secured to the transverse. support 23 and a trans-' verse support 33 which projects from the frame member 10 inspaced relation to and beyond the support 23. The clamping; mechanism 16 comprises'a guide. block 34 secured by screws-36 to a guide block support 37. The

; block-34nd the support '37 are rigidly secured in a transversely disposed opening formed .across' the support '33, by'two of a number of screws 38 which project through openingsformed in a" support 37 between the upper to. the lower parts thereof. The block 34 has'au opening formedtherein adapted to fit the wire 26 and through which/the wire 26 projects and is guided in its intermittent 'movement toward the ring forming mechanism 17. The block 34 also is formed in such a way as to provide atransversely disposed slot: 39 which projects across the block in such manner as to intersect the opening in which the wire 26 is 'slidably disposed. Projecting into the slot 39in such position as to engage an adjacent I surface of the wire 26, is the Wire engaging end of a clamping die indicated at 41. The clamping die 41'has the opposite end thereof disposed in engagement with a J tapering supporting block 42 disposed within sloping recess 43 which is formed in the end ,of a reciprocating .actuatinggnember indicated .at 44. The block 42 is, ad-

' justably positioned with respect to the member 44. by a screw 40-whichis threaded into the member 44 and which receives a nut 45 for use in securing the block 42 in the desired position. The clamping die 41 is secured in the recess 43 and against the block'42 by a screw 35 which is engaged in a threaded opening formed in the actuating member 44. The actuating member 44 is slidably disposed in aguideway formed in the support 33 in transverse relation to the path of movement of the wire 26 through the guide opening formed in the block34. The actuating member 44 is moved inwardly to clamp'the wire 26 between the die 41 and the block39 by a lever 46 which is, mounted upon a pin 47 for pivotal movement with respect tothe support 33, pin- 47 are rigidlysecured between lugs 48 projecting from t the support 33 and'between which the end of the lever 36. isv slidably di'spo'sed. The actuating member 44 is moved inwardly by a link; 51 having semispherical bear- 1 ing surfacesformed at opposite ends thereof which project into 'semispherical bearing openings formed in the adjacent end 'of the actuating member '44 and the adjacent surface of the'lev er 46. The actuating member 44' tendsi'to. be urged intoits retracted position and to follow the operation'of the lever 46 by e spring 52. which is secured in an opening formed'in the support 33 in parallel relation to the opening receiving the actuating'mema .ber;44 One end of the spring 52 is supported by the" 60 a-block 53 secured to the end of actuating member 44 by V support'33 whereas the other end of the spring engages a-screw indicated at 5.4.." The block 53 is mounted in a transversely disposed opening formed in the support 33 in such-a way as to provide clearance for the movement 7 t of the block 53 with the actuating 'member 44 and between the support 33 and a stop member 56. The

stop'membe'r 56 is-secured in 'a recess formed in the end wall of the-support33by a screwindicated at 57.

V The lever 46 is'provided at the end thereof opposite stlie,pin]47,s with a roller follower member" 53. The follower member is rotatably supported on a-pin 59secured' The opposite ends'of' the 7 projects. through an elongated openingin the die 41 and' 4 7 1 It will be apparent that rotation of the cam 62 by the shaft 11 will operate the lever 46 to move the actuating member 44 toward the wire 26. Also, the cam 62'and the eccentric 31 employed for operating the clamping head 19'are so timed with respect to one another that the die 41 will be actuated to clamp the wire 26 with respect to the guideway formed in the block 39 after the clamping head 19 has advanced a sufficient length V of the wire 26 to form a single piston ring. The die 41' holds the wire'26 rigidly with respect to the block 39 during the entire retracting movement of the clamping head 19 and is actuated by the cam 62 to release the wire 26 within the block 39 when the clamping head 19 clamps the wire 26 Within the block 24 at the beginning of the succeeding advancing movement of the head 19. 7 During such advancing movement a new length of 'the' wire 26 is advanced through the guideway formed in the block 39 to provide material for forming a succeeding piston ring;

The succeeding lengths of the wire 26 are formed 'hy the ring forming mechanism in such way as to provide 7 7 split piston rings or split piston ring blanks .or stock as indicated by the numeral 63. The ring forming mech-.

anism 17 is actuated by a rack 64, one end of which is secured rigidly to and'movable by the reciprocable clamp ing head 19. The opposite end of the rack is slidably disposed'inaguideway 66 which extends along one side of a support 67 formingthe body on which the mechanical elements of the ring forming mechanism: 17 are mounted; The support 67 is secured rigidly to the frame 10 in the proper relation to the other mechanical Within'the Z elements of the ring forming apparatus. support 67 the teeth of the rack 64 engage the teeth of a pinion 68 which-is formed 'on the hub. or sleeve: end

of a driving element 69 of an overrunningclutch 71.

The overrunning clutch 71 is similar to that shown by V the patent to De Lavaud 1,542,040, June 16, 1925; The inner driven element 72 of the=overrunning clutch 71 is secured by a key 73 to an' enlarged concentric partl74 formed intermediate the ends of. a driving-shaft 76for 'the operating elements of the ring forming mechanism l 17. A'plurality of earns .77 are disposed between t-he interior and exterior surfaces of the members 69. and

'between a pair of lugs 61 formed at the end of the:

lever- 46;. .Thejfollower 58f is adapted to engage a cam '62Irig'idlyfsecured onjthe 'shaftll in 'opposed relation: tothe plane ofmov'emeiitof'the lever 46.1 I

'72, respectively, for driving the shaft 76 in'o'ne'direc tion when the rack 64 is moved inwardly with respect: to the support 67 by the advancing movement "of the clampinghead 19. Movement of'the rack64'outwardly with respect to the support'67 by the retracting move-. a

ment' of the clamping head 19 .will' slightly rotate the cam members 77 to release the driven member 72 from;

the driving member 69 of the clutch 71 to avoid rotation of the shaft 76 in the opposite direction.

.In' order to insure the instantaneous release cams 77 upon the advancing movement of the rack 64 with respectv to the support 67, theend 9f the shaft 76' beyond'the clutch '71 is provided with a' friction brake indicated generally by the numeral 78.;The shaft 76f is rotatably supported between the overrunningclutch': '71 and the brake 78 within a bushing s79 that -is secured e in a cylindrical opening formed inan en wall of "a" affine.

housing member 81 which surroundstheoverruuning clutch 71 and which is secured to aside wall portionof the support 67 by screws or other suitablemeansnot shown. rigidly secured to the end of theshaft 76 by a pin'83. A brake arm 84 has a split ring 86-formed at one end' The brake 78 comprises a collar 82 which is thereof .whic-his adapted'to be expandedfor contracted with respect to the collar 82 by the operation of a screw 87 extending through a pair of lugs 88 projecting an upper portion of the housing 31. A screw 92 projecting through an opening in the end of the arm 84 secures the arm to the boss 91.

The end of the shaft 76 beyond the pinion 68 is rotatably supported in a bushing 93 which is rigidly secured in a cylindrical opening formed in the front side of the support 67. Between the bushing 93 and the pinion 68 is a driving pinion 94 which is keyed to the shaft 76 as is indicated at 96. The pinion 96 is adapted to engage and to drive a spaced pair of pinions 97 which are secured within the support 67 on the inner ends of a spaced pair of shafts indicated at 98. The shafts 98 are rotatably supported within the support 67 by bushings 99 which are secured in cylindrical openings formed within the front wall 101 of the support 67. The pinions 97 are secured upon the shafts 98 by keys not shown, and are secured against axial movement upon the reduced ends of the shafts 98 by screws and washers indicated at 102 and 103 respectively.

Disposed on the front wall 101 of the support 67 is a plurality of bending rollers indicated generally at 104. The bending rollers 104 comprise a spaced pair of supporting rollers 106 and 107 and a fulcrum roller indicated at 108. The supporting rollers 106 and 107 are disposed in spaced relation to one another and are secured rigidly upon the ends of the spaced and parallel shafts 98 by nuts 109 secured against washers 111 upon the threaded and reduced ends 112 of the shafts 98. The fulcrum roller is rotatably secured on the end of a stud 113 having an annular shoulder 114 and a threaded reduced end 116 which are rigidly secured in suitable openings formed in a slide member indicated at 117. The slide member 117 is slidably disposed in a guideway 11% formed within the front wall 101 of the support 67. The guideway 118 and the slide member 117 contained therein project across the space between the rollers 106 and 107 in such manner as to be perpendicular to a plane intersecting axes of the two rollers and midway between the axes of the two rollers.

It will be apparent that movement of the guide member 117 within the guideway 118 will move the roller 108 farther within or away from the space between the supporting rollers 106 and 107. The rollers 106 and 107 are formed in such a way as to provide annular grooves 119 in the peripheral surfaces thereof and adjacent the outer extremities of the rollers. The grooves 119 are only slightly greater in Width than the width of the wire 26 from which the rings 63 are formed, and are adapted to receive the wire 26 as the wire 26 is projected between the rollers 106 and 107 and the roller 108.

It will be apparent that the rack 64 will be actuated upon the advancing movement of the clamping head 19 to rotate the rollers 106 and 107 in a counterclockwise direction as the rollers appear in Figure 2. The rollers 106 and 107 therefore will tend frictionally to drive the wire 26 over the roller 108 when the wire is advanced by the operation of the intermittent feeding mechanism indicated at 14. Assuming that the roller 108 is adjusted to bend the section of wire supported between the rollers 106 and 107, it will be apparent that the movement of the wire 26 through the bending rollers 104 in response to the operation of the wire feeding mechanism 14 will tend continuously to bend the wire 26 while the wire is intermittently advanced.

Beyond the rollers 106 and 107 is a guide roller 121 which is adapted to guide and position the rings 63 in the region between the forming rollers 104 and the cutoff mechanism 18. The roller 121 is rotatably supported by a pin 122 secured in the bifurcated end of a bracket 123. The bracket 123 is adjustably secured upon the front wall 101 of the frame or support 67 by a screw 124 which projects through an elongated slot 126 with which the bracket 123 is provided. It will be apparent that proper adjustment of the'bracket 123 will cause the roller 121 to follow the exterior surfaces of the rings 63 as the later are being formed by the forming rollers 104.

In order to insure that the wire 26 may be started through the forming rollers 104 without too much difficulty, there is provided between the supporting rollers 106 and 107 a stop member 127 having an angularly formed end indicated at 128. It will be apparent that the end of the wire 26 will engage the end 128 when a new supply of wire is being started through the machine and that the stop member 127 will tend to bend the end of the wire in such manner as to tend to direct the wire beneath the roller 106 and Within the groove 119 formed in the roller 106. The stop member 127 may be adjusted as desired by operation of a lever 129 projecting from a shaft 131. The shaft 131 has an eccentric 132 which is disposed within a transverse slot 133 formed in the end of the stop member 127 remote from the rollers 106 and 107. Shaft 131 is rotatably secured in concentric bearing openings formed in a block 134 which is secured to the front wall 101 of the support 67 by screws indicated at 136. The member 127 is slidably disposed in a transversely disposed slot 137 which is formed in the block 134 in such a way as to intersect the shaft 131. The shaft 131 is secured in the block 134 by a snap ring indicated at 138. It will be apparent that rotation of the shaft 131 by the lever 129 will move the stop member 127 with respect to the rollers 106 and 107 by operation of the eccentric 132.

It will be apparent that movement of the fulcrum roller 10% toward and away from the space between the supporting rollers 106 and 107 will vary the curvature of the section of wire supported between the supporting rollers 106 and 107 as the wire 26 is formed to provide the ring 63. As the roller 108 moves toward the space between the rollers 106 and 107, the curvature of the wire section being formed will be increased and as the roller 103 moves away from the space between the rollers. 106 and 107 the curvature of the wire section being formed will be decreased. It is now proposed to provide means for varying the curvature of a length of the wire 26 required to make one of the rings 63. It is proposed to vary the curvature of such length of wire in such manner that the curvature of the length of wire will increase from the middle of the length toward the opposite ends thereof. The curvature of ring 63 formed in this manner will increase from the middle of the ring toward the opposite ends thereof. To so vary the curvature of the ring 63 it is proposed progressively to move the fulcrum roller 108 toward and away from the supporting rollers 106 and 107. To so move the roller 10!? the slide 117 is adapted to be moved in the guideway 118 by an adjusting mechanism indicated generally at 141. The adjusting mechanism 141 comprises a rod 142 having one end thereof secured in a threaded opening formed in the adjacent end of the slide member 117. The opposite end of the rod 142 supports a split circular ring nut 143 which may be rigidly secured upon the threaded end of the rod 142 by tightening a screw 145 disposed in a threaded opening intersecting the split end of the nut 143. The screw 145 may be loosened for adjustably positioning the nut 143 upon the end of the rod 142 by turning the nut 143 with a spanner wrench adapted to engage radial openings 144 formed in the periphery of the nut. The nut 143 is adapted to be engaged by t e flange end 146 of a sleeve 147 which surrounds the rod 142 and extends to within a short distance of the end of the slide member 117. The opposite end of the sleeve 147 is threaded in such manner as to receive and to have secured thereon a threaded collar indicated at 148. The sleeve 147 is slidably disposed in a bearing 149 formed in a cylindrical support 151 which is formed as an integral part of a supporting bracket indicated at 152. The supporting bracket 152 is secured rigidly by screws to an angularly disposed upper wall 153 which is formed amass ontlt inperpendicular relation to the path spring 154 is opposed by a cam operated lever indicated at 157. The lever is mounted intermediate the ends thereof upon a pin 158 which is secured between a pair of spaced supports 159 the lower ends of'which are formed integrally with respect to an integral wall 161 forming a part of the bracket 152.

The actuating-end of the lever 157 is formed in such 7 a way as to provide a yoke 162, the ends of which project on opposite sides of a part of the sleeve 147 below the. flange 146. The upper ends of the yoke 162 have semicylindrical fbearings 163 formed thereon which are adapted to project within semi-cylindrical openings formed in the lower surface of a bearing ring 160. This ring 160 is slidably disposed about the sleeve .147 adjacent the flange 146. V V V a V It will be apparentthatmovement of the lever 157 to elevate the sleeve 147 will tend to move the fulcrum roller 108 toward the space between the supporting rollers 106 and 107 to increase the curvature of thesection of wire. being supported between the rollers 106 and 107. The lever 157 may be moved in such manner as to increase the curvature of the wire being formed by. the

bending rollers 104 by a cam 164 which is secured by screws 166 upon the rotatably mounted shaft 13. The

exterior surface of the cam 164 is adapted to engage a roller follower 167- which is secured by a pin 168 in the bifurcated end 169 of the lever.157. For convenience in maintenance 'and assembly, the; cam 164'n1ay be formed in two parts indicated at 171 and 172. While it will be apparent that the exterior surface ofthe cam 164 may be formed in such a way as to provide a ring e 63 of any desired curvature, it is considered desirable to'form the cam 164 in such manner that the radii of curvature in opposite directions upon theisurface of the.

cam will increase at a relatively uniform rate from a minimum to a maximum radiusof curvature at diametrically opposed points on the surface of the cam 164.. The

exterior surface of the cam 164, as illustrated by Figure contacting the rollers 106 and 107 after the ring is formed, it has been found to be desirable to overbend a small section *ofthe Wire '26 at the junction of each lengthof the wire '26, used'in forming the rings 63. In order to'so overbend the. wire 26 in such regions and for such purposes, it has'been found desirable to provide the cam 164 with a hump 173, the surfaces forming the hump being 'of rapidly increasing and decreasing radii of curvature as compared to the moderately increasing and decreasing radii of curvature of the surfaces of the, section 172 of the cam 164 on opposite sides of the hump 173. l t will be apparent that the hump 173 will suddenly greatly accelerate the inward and outward movement of the roller 108 with respect to the rollers 106 and 107 at the junctions between the lengths of the wire 26 employed in forming successive rings 63.. In terms of the engagement of the surfaces of the camx164 with the follower 167 of the lever 157, the hump 173 will engage the follower 167 at the time when the surface of'thecam 164 engaging the follower 1 67 changes from an increasing to adecreasing radii of curvature. change in the movement of the lever 157 by the hump 173 will tend abruptly to bend the wire 26 at the junctions between the lengths of the wire 26 employed in forming successive piston rings indicated at 63.

The entire mechanism including the cam 164 is timed in such manner ,thata ring 63 will be formed and the'wire feeding mechanism. 14 will be stopped when the junctions between successive lengths of thewire 26 are diametrically opposed to the ringv forming rollers 104 and in the position of one of the junctions indicated at 174 which ap-- pears between the dot-and-dash lines intersecting the wire which represent sections of the wire which traverse the bending rollers 104 at the junctions of ,thest lccess'ive lengths of wire employed in forming the rings 63.

The cut-off mechanism 18 which is employed for such purposes comprises a block 176 which is secured to the support 67 in such manner that the front surface of the 7 block is in the plane of the inwardly disposed edge surfaces of the grooves 119 which are formed in the support;

ing rollers-106;;and 107 and through which the wire 26 7 passes during the bending of the wire to form rings such surface of the part 172 of thecam' 164 increases from V the ends toward the middle thereof at a similar relatively uniform rate. r

Referring to all of the figures of the drawing and par ticularly to Figure 7, it will be noted that the apparatus is shown with all of the mechanical elements thereof in the positions they assume after a ring 63 has been formed from the wire 26'and just prior to the timewhen the ring 63 is cut off from the wire26 by operation of the cut-off mechanism indieated at 18. The fact will be observed that in order to bend the wire 26 into the form of a ring 63 it is-necessary to bend the section of wire supported by the supporting rollers'106 and 107 to a curvature considerably exceeding the curvature which the corresponding part of the ring 63 will assume after it has traversed the bending rollers 104. 7 When such fact is considered rit will be apparent that the ring formed by the bending rollerswill tend to assume a position somewhat to the; right hand .side of'and above the axis of curvature of the section of: the wire supported by the it; is provideclwith an opening for receiving a die 177:;the

the cuttingend179 of; apunch indicated at 181. The

the ring 63" from assuming. such position andtoinsure V that'tli e ring 'will not be distoft ed again improperly as that indicated at 63.

rollers 104 will traverse the front surface of the block 176 with the adjacent surface of the wire in slidingfenogagement with the blo'ckI176.. A part of the block 176' latter having an opening 178 formed therein for receiving cutting end of the punch 1 79fwhich corresponds to the shape of the opening 178 will'be seen in Figure 2 to comin whi ch the non-parallel sides of a figure are indicated in dotted lines in Figure 2. The'non parallel sides of the cutting endljQ of the punch 181 are formedin such away as tobe disposed approximately normally to the 7 ends of section 174 of the Wire 26 so that the ends ofthev ring 63 will fbe formed with surfaces that close at the outer periphery thereof when the ring is contracted within.

a 'cylin der which such rings are employed.

The puh'c'h l til is slidably mounted in an opening Y .sfo'rmejd in one of aplurality of sections 182, 183 and 184 of steer supporting. head'indicated at 186. The

head .186. issecured to the frame member '10 by screws ns igat e sections of the-head186 indicated at 182, and 184; are likewise secured together :by; screws indicated at"188 Sli'dablyfdisposed in an-openingf formed in the sections 183 and 184 of'the head 186 and It willbe apparent that the abrupt Assuming the bending rollers 104 to be properly aligned and the wire 26'to be straight, it will be apparent that the wire 26 bent by the bending at one side of the opening receiving the punch 181 is a work holding member indicated at 189. The member 169 is disposed in spaced and parallel relation to the punch 181 and circumferentially beyond the blank 174 with reference to the formation of the wire 26 into one of the rings 63. The work holder 189 has an end surface formed in parallel relation to the front face of the block 176, the end surface referred to being normally spaced from the block 176 so that the wire 26 can extend between the work holder 189 and the block 176 during the formation of one of the rings 63. The punch 181 and the work holder 189 are adapted to be actuated by a cam mounted upon the hub of a flywheel 190 which is rigidly secured upon the shaft 11. The cam projects within a cam housing indicated at 191 which is secured rigidly to the frame 10. The cam referred to is adapted to operate a reciprocating tool actuating member 192 which is slidably mounted Within the housing 191 and which extends from the housing 191 into engagement with the punch 181. The work holder 189 is spring actuated by the tool actuating member 192 so that the spring will be compressed after the work holder 189 clamps the rings 63 successively against the block 176 and while the punch 131 is being projected into the dot-and-dash line position within the die 177. The dot-and-dash line position of the punch 181 referred to is illustrated by Figure 3. During the movement of the punch 131 from the full line to the dot-and-dash line positions illustrated by Figure 3, the blank 174 is cut from the junction between two lengths of the Wire 26 which are operated upon by the forming rollers 104 to provide one of the rings 63. The punch 181 projects the blank 174 through the die 177 and from the machine through successive openings 193 and 194 formed, respectively, in the block 176 and the adjacent part of a support 67.

It will be apparent from Figures 2, 3 and 7 that a ring 63 having a gap diametrically opposed to the forming rollers 104, cannot be formed without overlapping the adjacent convolutions of the wire 26 in the vicinity of the forming rollers 104. Since such overlapping of convolutions will tend to cause the rings 43 to be distorted out of the planes which it is desired to have the rings assume after the formation thereof, it is proposed to so modify the mechanism as to prebend the wire 26 and to so modify the rollers 106 and 107 with respect to the ring engaging surface of the block 176 that the rings 63 will be finally formed in the planular configuration desired.

To accomplish such end it is proposed positively to guide the rings 63 after the formation thereof by the forming rollers 104 by employing grooves 196 which are formed in the ends of the supporting rollers 106 and 107 in spaced relation to the grooves 119 formed therein. The rollers 106 and 107 also are chamfered at 197 around the peripheral surfaces thereof between the grooves 119 and 196. This is done for the purpose of directing the ends of the successive rings 63 into the guiding grooves 196 after the wire 26 has been bent by the bending rollers 104 while traversing the grooves 119 and the exterior surface of the roller 163. It will be noted from Figure 3 that the roller 10?; does not project outwardly as far as the grooves 196 so that the rings 63 are not engaged by the bending rollers 104 after the Wire 26 is originally formed by bending the Wire within the grooves 119 and between the fulcrum roller 108 and the supporting rollers 106 and 107. Assuming that the wire 26 employed in forming succeeding rings 63 must traverse and be guided and confined within the grooves 119 and 196, then it will be apparent that the front surface of the block 176 should be positioned in a plane which will cause the least possible distortion of the loop of the wire 26 that projects between the end surfaces of the punch 181 and the work holder 129 and the front surface of the block 176. It will be apparent from Figure 3 that sufiicient space is provided between the adjacent surfaces of the head 186 and the block 176 that the leading end of the ring 63 can be disposed in such space and without excessively distorting the wire employed'in forming the ring 63. It will also be apparent from Figure 7 that the leading end of the wire employed in forming the ring 63 will stop approximately at the adjacent edge of the cutting end 179 of the punch 181, when the advancement of the wire 26 is stopped between the formation of successive rings 63.

Since the grooves 196 and the ring engaging surface of the block 176 may slightly distort successive rings 63 being formed by the ring forming rollers 104, it is proposed to oppositely distort the wire 26 prior to the entrance of the wire into the groove 119 in the guiding roller 107 and between the guiding roller 107 and the opening in the block 39 from which the wire 26 emerge from the work holding or clamping mechanism indicated at 16. For so distorting the wire 26 it is proposed to employ a roller 198 having a groove 199 formed in the peripheral surface thereof for receiving the wire 26. The roller 198 is rotatably supported by a pin 201 having the ends thereof secured in a block 202 having a groove formed therein for receiving the roller 193 and across which the pin 201 extends. The block 202 is adjustably mounted in such manner as to be axially movable with respect to the roller 198, upon a support 203 which is secured to the support 67 by screws indicated at 204. The position of the block 202 may be adjusted by a lever 206 adapted to control the operation of a screw mechanism by which the roller 198 may be moved axially with respect to the wire 26. It will be apparent that axial movement of the roller 193 in the proper direction with respect to the roller 107 and the opening in the block 39 will progressively bend the wire 26 prior to its entrance into the bending rollers 104 and in such direction that the bending of the wire in spiral formation resulting from the formation of the successive rings 63 will tend merely to straighten the wire forming the ring 63 by bending the wire in a direction opposed to the preliminary bending established by the roller 198.

It will be apparent that the surfaces of progressively increasing and decreasing curvature formed on the cam 164 on opposite sides of the hump 173 will first progressively move the fulcrum roller 108 outwardly with respect to the supporting rollers 106 and 107 as the leading end of a length of wire required for the formation of one of the rings 63 progressively moves through the forming rollers 107 from the leading end to the middle of such length of wire. Thereafter such surfaces on the earn 164 will progressively move the fulcrum roller 108 inwardly with respect to the supporting rollers 106 and 107 as the length of wire progresses through the bending roller 104 from the middle toward the following end of such length of wire. Such movement of the fulcrum roller 108 will result in the formation of a ring 63 in which the curvature of the length of wire forming the ring will increase from the middle of the ring toward the opposite ends of the ring.

It has been found that when such a ring is confined within a cylinder in which the ring is designed to be employed, it can be made to exert practically uniform pressure against the interior surface of the cylinder and throughout the entire length of the ring.

it will be apparent that any desired modification of such uniform pressure exerted by one of the rings can be obtained by modifying the surface of the cam 164 to vary the bending of the ring to secure the pressure pattern desired. It has also been learned that for all practical purposes all of the variation in radius of curvature of the cam 164 may be applied to the part 172 of the cam where the surface of greatest radius of curvature is found. This may be done for the reason that the variation in radius of curvature required throughout the entire surface of the cam 164 excluding the hump 163 is so small, amounting to only a few thousandths of an inch in the entire cam, that a constant radius of curvature throughout the en ire extent a lie surface of he pm r the willnot noticeably affect'the'shapeof 'the r'ing 63 when 7 completed.

The Tings 63 may be successively-"removed mar ne grooves 196 in the bending orsupporting rollers 106 and 107 after the ringshave beenrelea'se'd by'operation'of the cut-ofi mechanism 18. I I r Whenthe rings have been so removed froin'themachine, they may be 'heatforined, set, tempered or nerm'alized 'in 'a 'heat treating furnace by the employment of -a heat'treating fixture such as that illustrated b' 'Fi ur'e 4; The heat treating apparatus shown 4 prises a heat treatingfu'rn'ace 207 having'a series of hooks projecting from the upper'vv'all thereof, on'whicha plurality *ofheat treating fixtures such as that indicated at20 9 niay be'hun'g; The rurnaee mey' be'heatedin any suitable manner a'sby theeniploymentbf electi'ical'heatle elements 'indic'at'ed'at 211. The xture- 262m prises a ring supportinginandre 2 'tllr gh which a rod 213 is adapted to"project"b en end latesindiwith re'sp ect t'o end'plate 214 and'frbin which "thej iixture- 209 is adapted to be hun py an'e'ye 21? forming the head of the belt 213. e' efi-d theend flare-nettl bolt ZIS is'threaded to receive a nut zitlbythetightening or which the distance between the plates 214 End-216m be varied. A stack 219 of therings 63 .is adapte'd to be disposed on the 'ext'erior' -suiofac'eof the 'mandre1212 with the gaps in the rings of the stack in alignment with one another. The rings inthe stack219fmay be clam ped in rigid relation to one another upon the mandrel212 by clamping rings 221 which'are scented to the innersurfaces of the end plates 214 and 216 positions'as to be directly opposite the ends of the ring 'stack 219 disposed upon the mandrelj212; The thickness "01:: the

ringsj221 is somewhat less thanthe thi'cliriessof the rings 63 in the stack 219 and the diameter of the ringsi sufficient to receive the ends of the mandrel 212 internally thereof. The rings in the stack 219 may 'be clamped against the exterior surface of the manager 212 by'a plu- -rality of clamping bars 222 which are'adapted to be disp'o'sed outside of the ring stack 219, to extend from one endto another ofthe ring stackandrinparallel relation to the axis of the mandrel 212;. The bars 222 may be clamped against the ring stack 219 by screws 223 which project through a plurality of'rings 2 24 that'surround'the bars 222 and that are spaced from one another throughout the length of the bars '222. The rings 224 are spaced with respect to one another soas to be held in proper relation to the bars 222 fra'rn'e rnernbers indicated at The external configuration'of the mandrel 212 'is'such that therin'gs 63 may be clamped by the bars 222 to the exterior surface thereof" practically without distorting the rings from the configuration in which the rings are formed similar to the configuration of exterior surface of the mandrel '212 thanlif the rings are formedaccording to some, other configuration and are bent into the configuration of the'exterior surfacefof the 'mandrel212 by operationot the clamping'bars 222. a v V v It will be apparent that the rings in the stack 219 will be positionedupon the mandrel'2l2 with the surface of leas't curvature on the mandrel21'2 opposite the middle portionof the rings. inthering stack 219 a'ndwith the surface of greatest curvature on the mandrel'in opposed relatiori tothe ends'of thefring's on 'oppos'ite'sides ofthe. aligned gaps therein.

When the rings j are so clamped within, the fixture 209 the fixture may be suspfinded in the heat treatingfumace'207 by hanging theeye 217 upon one of the hooks 8.

aims been found that atm eramrj ota-0a 1100 0 isv a'suitabl'e temperaturefor "normalizing staicks ofrings made from steel wire so formed and confined within fixtures 'su'eh as that iridicated at'209fandto beheattreatd '20 cat'ed at 214'and'216. Theme 21 is rigidly secured in' a heat tr'a'ting' furnace such as that indicated at 207.

H .v v l. A method of making piston rings which eomprises projecting agplurality of successive lengths ofacontinuo'us wire between bending rollers for continuouslyfbending s aid wire in one direction, moving the 'fulcrurn roller away from the supporting rollers or said bending rollers intermediate the-junctions between saidsuc'ces's'ive lengths and toward said supporting rollers at said junctions. 'between said lengths and during thefforniatio'n of one ring from each of said lengths, abruptly changing the movement of said supporting roller toward and away from said supporting rollers in the immediate vicinityof each of said successive'junctions to accentuate the curvature of [said lengths adjacent said junctions, and thereafter cutting out blanksfrom said wirefa't said junctions to include said accentuated curvature of said wire formed at said junctions.

2. ring forming machine comprising a plurality, of

bending rollers for continuously bending successive lengths of a continuous wire in one direction and .at the same increasing and decreasing curvature jforea'ch of said lengths, a cam for relatively moving s'aidQberiding rollers forincreasing and decreasing said curvature, .r'neansfor cutting a blank. from said wire at the junctionbetween the portions of gr'eatest curvature in successive lengths of said wire and drive means for driving said can; and said bending rollers in timed relation, said jtiniedrlation being suchithat said cam rotatesrone revolution as said bending rollers bend one convolution in each length'of saidwire V. 1 7

i 3; A ring forming machine comprisinga plurality of forming rollers for successively bending. continuous lengths of wire in one direction, 'a-cauigfor relatively moving said bending rollersf o r varying thecurvature of bythe ring forming apparatus previously disclosed. The a force exerted by the bars 222 upon the exterior surface of the ringsta'ck 219 therefore will beonly the minimum :force required to rigidly clamp the rings against the exterior surface of the mandrel 212 its-preventdistortion of the rings during the process of'he'at treating the'rings in the furnace 207.. Due to the factthat the individual rings 'inthe stack 219 are not appreciably distorted by s'aid wir'eirom one end toanother of said lengths, cut-ofi means having the opposed cutting edges thereof disposed normally withures pect to the curvature of said wire for cuttin'g'a blank fromzsaid Wire at the .juuctions between said succ'essive lengths of wire and drive means for drivclamping therings to the exterior surface of the mandrel I 212 it will'be apparent that the heat treatment required the furnace 206 will be only theminimum amount of heat itreatnient required to release the internal stressesin the rings caused by the bending or the wire 26in the ring bending apparatus referred tog Since the time required for normalizing the internal stres'sesin therin'gs is' prop'o'rtional to'the extent to which the molecules of thefrna'te'rial must be rearra ged withinthe rings, nw'i'l'l be apparent that a shorter time'will be required to nor-f maliz'e the internal stresses-in {the 'ringsif the ringsjare' formed by. the ring forming apparatus in a configuration ing said earn and said bending rollers in timed relation, said timed relation being such that said cam rotates one revolution as said bending rollers bend one convolution iii each length of said wire.

' References Cited in the file of this patent Squibb V Oct. 13, 1953 

